The invention relates to a device for pushing glass objects from a dead plate of an I.S. glassware forming machine onto a conveyor belt.
Such devices are intended to transfer the glass object, in particular a hollow glass object, which has been removed from a blow-mold of a glassware forming machine and placed on a stationary dead plate. The device then transfers the glass object by means of a pusher to a conveyor belt moving continuously at a uniform speed. The glass objects must be positioned on the conveyor belt one behind the other to be subsequently introduced into a lehr. In the case of I.S. (individual section) machines where the conveyor belt co-operates with a plurality of manufacturing stations, each of which is provided with a dead plate, the process of pushing the glass objects must take place within a time interval dependent upon the operating cycle of the remaining manufacturing stations and upon the transport speed of the belt. Moreover, the pushing procedure must be performed so as to avoid toppling of or damage to the glass objects and imprecise positioning on the belt. At the end of the movement along a transfer curve, each glass object must be arranged in a defined position on the belt and move with it in the same direction and at the same speed.
Document DE 10 2004 010 238 133 discloses a device of this type in which a first lever which at one of its ends can pivot about a vertical, positionally-fixed axis supports at its other end one end of a second lever which can also pivot about a vertical axis, the other end of the second lever having a pusher mounted thereon, said pusher in turn being pivotable about a perpendicular axis and being fitted with three pushing fingers. Allocated to the rotations of the first lever about the positionally-fixed axis, of the second lever with respect to the first lever and of the pusher with respect to the second lever are three positionally-fixed drives which can be controlled in a mutually independent manner, wherein a transfer curve beginning at a point of reception on the dead plate and ending at a point of delivery on the conveyor belt can be produced by the superposition of the three partial movements generated by the drives. The transfer of the rotational movements of the three drives via the levers to the pusher is effected by means of toothed belt gear mechanisms, the operation of which requires a great deal of maintenance. This is accompanied by a comparatively large constructional outlay which is governed by an initial combination of the driving movements of three fixedly disposed drives via hollow shafts guided one inside the other and subsequent separation of these movements for their introduction into the respective component whose rotational movement is to be controlled.
Document DE 2008 027 911 A1 discloses a further comparable device in which the pusher is fixedly connected to the end of a crank arm which is connected to a shaft in a rotationally-fixed manner, said shaft being mounted in a rotatable manner on a rotary disk eccentrically with respect to its positionally-fixed axis extending in parallel with said shaft. Said shaft forms the driven shaft of a first electric motor also supported by the rotary disk, wherein the rotary disk is drivingly connected directly with a second, positionally-fixed electric motor. This design indeed allows a simplification in the gear elements necessary for transferring the partial movements of the two electric motors, wherein, however, in comparison with the device known from document DE 10 2004 010 238 B3, there are fewer design options for producing a transfer curve since only two partial movements are to be superposed and the pusher is not pivoted with respect to said crank arm.
Finally, EP 1 886 977 A1 discloses a further device for pushing glass objects onto a conveyor belt, in which two electric motors disposed in a machine frame coaxially with respect to each other are fixedly connected to crank arms at the respective ends of their driven shafts, wherein the free end of one crank arm is articulated via a joint directly on a structure supporting a pusher and wherein the free end of the other crank arm is articulated via a joint with an intermediate lever and this, at its end remote from the crank arm, is articulated via a further joint on said structure. The axes of all the joints extend in parallel with each other. By controlling the two electric motors to rotate in the same direction, it is possible to produce a rotational movement of the pusher about the common axis of the two motors, wherein by way of the control to rotate in the same direction, it is possible to move the pusher closer to or further away from a dead plate or a conveyor belt. The transfer curve starting from a dead plate to a conveyor belt is thus a circular arc about the common axis of the two motors. Since only two partial movements are to be superposed, there are also fewer design options for the transfer curve in the case of this device compared with that described in document DE 10 2004 010 238 B3.